Scientists Develop Edible Sensors to Detect Food Spoilage

Can't decide if that milk is just one day past its prime? Trying to figure out if it's time to cut that pineapple on the window sill? Wonder no more. Scientists at Tufts University have created edible silk sensors that can be applied to any food or float in liquids to inform you when your food has hit peak ripeness or when it's spoiled rotten.

The sensors are made from silk and gold (fancy, huh?) and are tiny, thin stickers that are small enough to be placed on cherry tomatoes. You may wonder if you can really eat silk and gold. According to the research study, which was published in Advanced Materials, "These types of passive, chip-less sensor consist of an antenna or an array of antennas/resonators made of only a sub-micron thickness of gold, a level equivalent to common edible gold leaf/flakes used on cakes and chocolates." And silk? It's actually a protein that will "safely interface with consumable goods or can be in direct contact with food." But if you don't want to eat the sensors, you can just slice them off of the food and dispose of them. Good news — they are also biodegradable.

Glue isn't necessary to hold the sensor on your food. According to Co.Exist.com, "The silk film doubles up as the sensor's glue, turning sticky when exposed to water. The sensor is then pasted directly onto the food that needs tracking, eliminating the need for an additional glue to keep it clinging on." The researchers tested the effectiveness of the sensors on bananas, eggs, apples, cheese, and even milk.

But how does this little sticker actually work? "When a fruit ripens or rots, chemical changes churn around inside it. Those changes and differences in the stiffness of the fruit translate to what's called their dielectric properties," explains FastCoexist.com. The gold detects those changes and then emits an electromagnetic signal. "We can tailor our sensor to be extremely sensitive to the change of the dielectric property," Hu "Tiger" Tao, a Tufts researcher on the project, explained to Co.Exist.com.

While it sounds like a nifty way to monitor those bananas, the researchers are banking on this scientific breakthrough to help manufacturers and suppliers better manage food safety.

"Food safety is an increasingly important public health issue for both the consumer and food industry," the study noted. Researchers believe using the sensors could aid quality control of agricultural and biological food products in the future.